# std::holds_alternative

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< cpp‎ | utility‎ | variant

Defined in header `<variant>` |  |
template< class T, class... Types > constexpr bool holds_alternative( const std::variant<Types...>& v ) noexcept; |  | (since C++17)

Checks if the variant v holds the alternative `T`. The call is ill-formed if `T` does not appear exactly once in `Types...`

### Parameters

v | - | variant to examine

### Return value

true if the variant currently holds the alternative `T`, false otherwise.

### Example

Run this code

    #include <cassert>
    #include <string>
    #include <variant>

    int main()
    {
        std::variant<int, std::string> v = "abc";
        assert(not std::holds_alternative<int>(v));
        assert(std::holds_alternative<std::string>(v));
    }

### See also

index | returns the zero-based index of the alternative held by the `variant` (public member function)
get(std::variant) (C++17) | reads the value of the variant given the index or the type (if the type is unique), throws on error (function template)

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